V8 SpiderMonkey JavaScriptCore Chakra Carakan KJS Other
⬤ Minor difference (1 point) ⬤ Small feature (2 points) ⬤ Medium feature (4 points) ⬤ Large feature (8 points)
Compilers/polyfills Desktop browsers Servers/runtimes Mobile
Feature name Current browser ES6
Trans-
piler		 Traceur Babel +
core-js[2]		 Closure JSX Type-
Script +
core-js		 Type-
Script +
core-js		 Type-
Script +
core-js		 Type-
Script +
core-js		 Type-
Script +
core-js		 Type-
Script +
core-js		 es6-shim Konq 4.14[3] IE 10 IE 11 Edge 12 Edge 13 Edge 14 Edge 15 Edge 16 Edge 17 Preview FF 45 ESR FF 51 FF 52 ESR FF 53 FF 54 FF 55 FF 56 FF 57 FF 58 FF 59 Beta FF 60 Nightly OP 12.10 CH 56,
OP 43[1]		 CH 57,
OP 44[1]		 CH 58,
OP 45[1]		 CH 59,
OP 46[1]		 CH 60,
OP 47[1]		 CH 61,
OP 48[1]		 CH 62,
OP 49[1]		 CH 63,
OP 50[1]		 CH 64,
OP 51[1]		 CH 65,
OP 52[1]		 CH 66,
OP 53[1]		 SF 8 SF 9 SF 10 SF 10.1 SF 11 SF 11.1 SF TP WK Rhino 1.7 PJS Echo JS XS6 JXA Node 0.10[4] Node 0.12[5] Node 4[5] Node >=6.5 <7[5] Node 7.0-7.5[5] Node >=7.6 <8[5] Node 8.0-8.2[5] Node >=8.3 <8.7[5] Node >=8.7 <9[5] DUK 1.5 DUK 1.6 DUK 1.7 DUK 1.8 DUK 2.0 DUK 2.1 DUK 2.2 AN 4.4 AN 4.4.3 iOS 8 iOS 9 iOS 10.0-10.2 iOS >=10.3 <11 iOS 11 JJS 1.8 JJS 9
Optimisation
§proper tail calls (tail call optimisation) 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 0/2 0/2
§direct recursion No Flag[6] No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No No No No No No No No No No No No No No No No No No Flag[8] Flag[8] No[9] No[9] No[9] No No No No No No No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Flag[8] Flag[8] Flag[8] No[9] No[9] No No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§mutual recursion No Flag[6] No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No No No No No No No No No No No No No No No No No No Flag[8] Flag[8] No[9] No[9] No[9] No No No No No No No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Flag[8] Flag[8] Flag[8] No[9] No[9] No No No No No Yes Yes Yes No No No No Yes Yes Yes No No
Syntax
§default function parameters MDN (Mozilla Development Network) logo  4/7 4/7 4/7 5/7 0/7 5/7 5/7 5/7 5/7 5/7 5/7 0/7 0/7 0/7 0/7 0/7 0/7 7/7 7/7 7/7 7/7 4/7 6/7 6/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 0/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 0/7 0/7 7/7 7/7 7/7 7/7 7/7 7/7 0/7 0/7 4/7 7/7 0/7 0/7 0/7 0/7 7/7 7/7 7/7 7/7 7/7 7/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 7/7 7/7 7/7 0/7 4/7
§basic functionality Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No Flag[10] Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§explicit undefined defers to the default Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No Flag[10] Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§defaults can refer to previous params Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No Flag[10] Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§arguments object interaction Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§temporal dead zone No No No Yes No Yes Yes Yes Yes Yes Yes No No No No Flag[10] Flag[10] Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§separate scope No No No Yes No No No No No No No No No No No Flag[10] Flag[10] Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§new Function() support No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Flag[10] Flag[10] Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No[0] Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§rest parameters MDN (Mozilla Development Network) logo  2/5 4/5 3/5 2/5 3/5 4/5 4/5 4/5 4/5 4/5 4/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 3/5 5/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 0/5 0/5
§basic functionality Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§function 'length' property Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§arguments object interaction No Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§can't be used in setters No Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§new Function() support No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No[0] Yes No No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§spread (...) operator MDN (Mozilla Development Network) logo  8/15 15/15 13/15 12/15 2/15 4/15 4/15 4/15 4/15 4/15 4/15 0/15 0/15 0/15 0/15 12/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 0/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 5/15 9/15 15/15 15/15 15/15 15/15 15/15 15/15 0/15 0/15 10/15 15/15 11/15 0/15 0/15 0/15 15/15 15/15 15/15 15/15 15/15 15/15 0/15 0/15 0/15 0/15 0/15 0/15 0/15 0/15 0/15 5/15 9/15 15/15 15/15 15/15 0/15 0/15
§with arrays, in function calls Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with arrays, in array literals Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with sparse arrays, in function calls Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with sparse arrays, in array literals No Yes No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with strings, in function calls No Yes Yes[11] Yes No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§with strings, in array literals No Yes Yes[11] Yes No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with astral plane strings, in function calls No Yes Yes[11] No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§with astral plane strings, in array literals No Yes Yes[11] No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with generator instances, in calls No Yes Yes[11] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§with generator instances, in arrays No Yes Yes[11] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§with generic iterables, in calls Yes[12] Yes Yes[11] Yes No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§with generic iterables, in arrays Yes[12] Yes Yes[11] Yes No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with instances of iterables, in calls Yes[12] Yes Yes[11] Yes No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§with instances of iterables, in arrays Yes[12] Yes Yes[11] Yes No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§spreading non-iterables is a runtime error Yes Yes No Yes No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§object literal extensions MDN (Mozilla Development Network) logo  6/6 6/6 6/6 4/6 5/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 1/6 5/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 5/6 6/6 5/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 4/6 4/6 4/6 0/6 0/6 1/6 5/6 6/6 6/6 6/6 0/6 2/6
§computed properties Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes No No
§shorthand properties Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No Yes
§shorthand methods Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes[13] Yes[13] Yes[13] Yes[13] Yes[13] Yes[13] Yes[13] Yes[13] Yes[13] Yes[13] Yes[13] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No Yes
§string-keyed shorthand methods Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§computed shorthand methods Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§computed accessors Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§for..of loops MDN (Mozilla Development Network) logo  4/9 9/9 9/9 6/9 2/9 3/9 3/9 3/9 3/9 3/9 3/9 0/9 0/9 0/9 0/9 6/9 7/9 7/9 9/9 9/9 9/9 7/9 7/9 7/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 2/9 8/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 0/9 7/9 9/9 8/9 0/9 7/9 7/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 2/9 8/9 9/9 9/9 9/9 0/9 4/9
§with arrays Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§with sparse arrays Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§with strings No Yes Yes[11] Yes No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§with astral plane strings No Yes Yes[11] No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§with generator instances No Yes Yes[11] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§with generic iterables Yes[12] Yes Yes[11] Yes No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with instances of generic iterables Yes[12] Yes Yes[11] Yes No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§iterator closing, break No Yes Yes[11] No No No No No No No No No No No No No No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§iterator closing, throw No Yes Yes[11] No No No No No No No No No No No No No No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§octal and binary literals 2/4 2/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 2/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 2/4 4/4 4/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 0/4 2/4
§octal literals Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes No Yes
§binary literals Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes No Yes
§octal supported by Number() No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes No No
§binary supported by Number() No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes No No
§template literals MDN (Mozilla Development Network) logo  3/5 4/5 4/5 3/5 4/5 3/5 3/5 3/5 3/5 3/5 3/5 0/5 0/5 0/5 0/5 4/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 4/5 5/5 5/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5 0/5 3/5
§basic functionality Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§toString conversion No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§tagged template literals Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§passed array is frozen Yes Yes Yes No Yes No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§line break normalisation No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§RegExp "y" and "u" flags MDN (Mozilla Development Network) logo  0/5 3/5 3/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 2/5 5/5 5/5 5/5 5/5 5/5 2/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 2/5 2/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 0/5 0/5
§"y" flag No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"y" flag, lastIndex No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"u" flag No Yes Yes No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"u" flag, Unicode code point escapes No Yes Yes No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"u" flag, case folding No Yes Yes No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§destructuring, declarations MDN (Mozilla Development Network) logo  14/22 20/22 21/22 20/22 12/22 15/22 15/22 15/22 15/22 15/22 15/22 0/22 0/22 0/22 0/22 0/22 0/22 21/22 22/22 22/22 22/22 19/22 21/22 21/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 0/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 9/22 19/22 22/22 22/22 22/22 22/22 22/22 22/22 0/22 0/22 12/22 21/22 19/22 0/22 0/22 0/22 22/22 22/22 22/22 22/22 22/22 22/22 0/22 0/22 0/22 0/22 0/22 0/22 0/22 0/22 0/22 9/22 19/22 22/22 22/22 22/22 0/22 0/22
§with arrays Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with sparse arrays Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with strings Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with astral plane strings No Yes Yes[11] No No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with generator instances No Yes Yes[11] Yes No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§with generic iterables No Yes Yes[11] Yes No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with instances of generic iterables No Yes Yes[11] Yes No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§iterator closing No Yes Yes[11] No No No No No No No No No No No No No No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§trailing commas in iterable patterns Yes No Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with objects Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§object destructuring with primitives Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§trailing commas in object patterns Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§throws on null and undefined Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§computed properties Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§multiples in a single var statement Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§nested Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§in for-in loop heads No Yes Yes[11] Yes No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§in for-of loop heads Yes Yes Yes[11] Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§in catch heads No Yes Yes[11] Yes Yes No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§rest Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§defaults Yes Yes Yes[11] Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§defaults, let temporal dead zone No No Flag Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§destructuring, assignment MDN (Mozilla Development Network) logo  17/24 23/24 24/24 21/24 11/24 19/24 19/24 19/24 19/24 19/24 19/24 0/24 0/24 0/24 0/24 0/24 0/24 23/24 24/24 24/24 24/24 21/24 23/24 23/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 12/24 21/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 14/24 24/24 21/24 0/24 0/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 12/24 21/24 24/24 24/24 24/24 0/24 0/24
§with arrays Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with sparse arrays Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with strings Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with astral plane strings No Yes Yes[11] No No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with generator instances No Yes Yes[11] Yes No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§with generic iterables No Yes Yes[11] Yes No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with instances of generic iterables No Yes Yes[11] Yes No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§iterator closing No No Yes[11] No No No No No No No No No No No No No No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§iterable destructuring expression Yes Yes Yes[11] Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§chained iterable destructuring Yes Yes Yes[11] Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§trailing commas in iterable patterns Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with objects Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§object destructuring with primitives Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§trailing commas in object patterns Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§object destructuring expression Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§parenthesised left-hand-side is a syntax error No Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§chained object destructuring Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§throws on null and undefined Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§computed properties Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§nested Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§rest Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§nested rest No Yes Yes[11] Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§empty patterns Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§defaults Yes Yes Yes[11] Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§destructuring, parameters MDN (Mozilla Development Network) logo  15/24 19/24 21/24 18/24 12/24 16/24 16/24 16/24 16/24 16/24 16/24 0/24 0/24 0/24 0/24 0/24 0/24 22/24 23/24 23/24 23/24 18/24 20/24 21/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 10/24 18/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 12/24 23/24 18/24 0/24 0/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 10/24 18/24 24/24 24/24 24/24 0/24 0/24
§with arrays Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with sparse arrays Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with strings Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§with astral plane strings No Yes Yes[11] No No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with generator instances No Yes Yes[11] Yes No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§with generic iterables No Yes Yes[11] Yes No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with instances of generic iterables No Yes Yes[11] Yes No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§iterator closing No No Yes[11] No No No No No No No No No No No No No No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§trailing commas in iterable patterns Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§with objects Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§object destructuring with primitives Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§trailing commas in object patterns Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§throws on null and undefined Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§computed properties Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§nested Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§'arguments' interaction Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§new Function() support No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No Flag[10] Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§in parameters, function 'length' property Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§rest Yes Yes Yes[11] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§empty patterns Yes Yes Yes[11] Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§defaults Yes Yes Yes[11] Yes No Yes Yes Yes Yes Yes Yes No No No No No Flag[10] Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§defaults, separate scope No No No Yes No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§defaults, new Function() support No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No Flag[10] Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No[0] Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§defaults, arrow function No No Yes No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Unicode code point escapes 1/2 1/2 1/2 1/2 0/2 1/2 1/2 1/2 1/2 1/2 1/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 1/2 1/2 1/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 0/2 0/2
§in strings Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§in identifiers No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§new.target MDN (Mozilla Development Network) logo  0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 1/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 1/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 0/2 0/2
§in constructors No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No Yes No No No No Yes Yes Yes No No
§assignment is an early error No No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
Bindings
§const MDN (Mozilla Development Network) logo  10/16 14/16 14/16 14/16 0/16 14/16 14/16 14/16 14/16 14/16 14/16 0/16 2/16 0/16 12/16 12/16 12/16 16/16 16/16 16/16 16/16 12/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 2/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 1/16 1/16 16/16 16/16 16/16 16/16 16/16 16/16 0/16 1/16 8/16 16/16 10/16 1/16 1/16 9/16 16/16 16/16 16/16 16/16 16/16 16/16 1/16 1/16 1/16 1/16 2/16 2/16 2/16 1/16 1/16 1/16 1/16 16/16 16/16 16/16 12/16 16/16
§basic support Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§is block-scoped Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§cannot be in statements Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§redefining a const is an error Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§for loop statement scope Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§for-in loop iteration scope No Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§for-of loop iteration scope No Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§temporal dead zone No No Flag No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§basic support (strict mode) Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Flag Flag Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No No Yes Yes Yes Yes Yes
§is block-scoped (strict mode) Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes
§cannot be in statements (strict mode) Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes
§redefining a const (strict mode) Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§for loop statement scope (strict mode) Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes
§for-in loop iteration scope (strict mode) No Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§for-of loop iteration scope (strict mode) No Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§temporal dead zone (strict mode) No No Flag No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes
§let MDN (Mozilla Development Network) logo  8/12 10/12 10/12 10/12 0/12 10/12 10/12 10/12 10/12 10/12 10/12 0/12 0/12 0/12 10/12 10/12 10/12 12/12 12/12 12/12 12/12 10/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 8/12 12/12 0/12 0/12 0/12 6/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 12/12 12/12 12/12 10/12 12/12
§basic support Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§is block-scoped Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§cannot be in statements Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§for loop statement scope Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§temporal dead zone No No Flag No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§for/for-in loop iteration scope No Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§basic support (strict mode) Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes
§is block-scoped (strict mode) Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes
§cannot be in statements (strict mode) Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes
§for loop statement scope (strict mode) Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes
§temporal dead zone (strict mode) No No Flag No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes
§for/for-in loop iteration scope (strict mode) No Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§block-level function declaration[15] No Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
Functions
§arrow functions MDN (Mozilla Development Network) logo  8/13 11/13 9/13 10/13 8/13 9/13 9/13 9/13 9/13 9/13 9/13 0/13 0/13 0/13 0/13 8/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 0/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 0/13 0/13 13/13 13/13 13/13 13/13 13/13 13/13 0/13 0/13 7/13 12/13 0/13 0/13 0/13 9/13 13/13 13/13 13/13 13/13 13/13 13/13 0/13 0/13 0/13 0/13 0/13 0/13 0/13 0/13 0/13 0/13 0/13 13/13 13/13 13/13 0/13 6/13
§0 parameters Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§1 parameter, no brackets Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§multiple parameters Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§lexical "this" binding Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"this" unchanged by call or apply Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§can't be bound, can be curried Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§lexical "arguments" binding No Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§no line break between params and => No Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§correct precedence No Yes No Yes No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§no "prototype" property No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§lexical "super" binding in constructors Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§lexical "super" binding in methods Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§lexical "new.target" binding No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§class MDN (Mozilla Development Network) logo  17/24 17/24 19/24 13/24 16/24 19/24 19/24 19/24 19/24 19/24 19/24 0/24 0/24 0/24 0/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 16/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 22/24 24/24 18/24 0/24 0/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 16/24 24/24 24/24 24/24 0/24 0/24
§class statement Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§is block-scoped No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§class expression Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§anonymous class Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§constructor Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§prototype methods Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§string-keyed methods Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§computed prototype methods Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§optional semicolons Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§static methods Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§computed static methods Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§accessor properties Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§computed accessor properties Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§static accessor properties Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§computed static accessor properties Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§class name is lexically scoped Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§computed names, temporal dead zone No No No No No Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§methods aren't enumerable No No Yes No Yes No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§implicit strict mode Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§constructor requires new No No Yes No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§extends No[16] No[16] No[16] No[17] No[17] No[18] No[18] No[18] No[18] No[18] No[18] No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§extends expressions No[16] No[16] No[16] No No[17] No[18] No[18] No[18] No[18] No[18] No[18] No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§extends null Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§new.target No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§super MDN (Mozilla Development Network) logo  7/8 7/8 4/8 6/8 7/8 7/8 7/8 7/8 7/8 7/8 7/8 0/8 0/8 0/8 0/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 6/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 0/8 6/8 8/8 7/8 0/8 0/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 6/8 8/8 8/8 8/8 0/8 0/8
§statement in constructors Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§expression in constructors Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§in methods, property access Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§in methods, method calls Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§method calls use correct "this" binding Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§constructor calls use correct "new.target" binding No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§is statically bound Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§super() invokes the correct constructor Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§generators MDN (Mozilla Development Network) logo  0/27 24/27 24/27 16/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 27/27 27/27 27/27 27/27 27/27 25/27 25/27 25/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 0/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 0/27 0/27 27/27 27/27 27/27 27/27 27/27 27/27 0/27 0/27 16/27 27/27 0/27 0/27 0/27 20/27 27/27 27/27 27/27 27/27 27/27 27/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 27/27 27/27 27/27 0/27 0/27
§basic functionality No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§generator function expressions No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§correct "this" binding No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§can't use "this" with new No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§sending No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%GeneratorPrototype% No Yes Yes[19] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%GeneratorPrototype% prototype chain No Yes Yes[19] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%GeneratorPrototype%.constructor No No No No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%GeneratorPrototype%.throw No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%GeneratorPrototype%.return No Yes Yes[19] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§yield operator precedence No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§yield *, arrays No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§yield *, sparse arrays No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§yield *, strings No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§yield *, astral plane strings No Yes Yes[19] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§yield *, generator instances No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§yield *, generic iterables No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§yield *, instances of iterables No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§yield * on non-iterables is a runtime error No Yes No No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§yield *, iterator closing No Yes Yes[19] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§yield *, iterator closing via throw() No Yes Yes[19] No No No No No No No No No No No No No Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§shorthand generator methods No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§string-keyed shorthand generator methods No Yes Yes[19] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§computed shorthand generators No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§shorthand generator methods, classes No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§computed shorthand generators, classes No Yes Yes[19] Yes No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§shorthand generators can't be constructors No No Yes[19] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
Built-ins
§typed arrays MDN (Mozilla Development Network) logo  0/46 0/46 45/46 0/46 0/46 45/46 45/46 45/46 45/46 45/46 45/46 0/46 8/46 16/46 16/46 42/46 44/46 46/46 46/46 46/46 46/46 42/46 45/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 18/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 18/46 18/46 46/46 46/46 46/46 46/46 46/46 46/46 0/46 18/46 37/46 46/46 46/46 19/46 23/46 43/46 46/46 46/46 46/46 46/46 46/46 46/46 17/46 17/46 17/46 17/46 19/46 20/46 20/46 19/46 19/46 18/46 18/46 46/46 46/46 46/46 19/46 20/46
§Int8Array MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Uint8Array MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Uint8ClampedArray MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Int16Array MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Uint16Array MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Int32Array MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Uint32Array MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Float32Array MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Float64Array MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Int8) MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Uint8) MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Int16) MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Uint16) MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Int32) MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Uint32) MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Float32) MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Float64) MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§ArrayBuffer[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§constructors require new No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes
§constructors accept generic iterables No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§correct prototype chains No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No Yes Yes No No No No Yes Yes Yes No No
§%TypedArray%.from MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.of MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.subarray MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§%TypedArray%.prototype.join MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.indexOf MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.lastIndexOf MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.slice MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.every MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.filter MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.forEach MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.map MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.reduce MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.reduceRight MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.reverse MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.some MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.sort MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.copyWithin MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.find MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.findIndex MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.fill MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.keys MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.values MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype.entries MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§%TypedArray%.prototype[Symbol.iterator] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No Yes
§%TypedArray%[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Map MDN (Mozilla Development Network) logo  0/19 14/19 19/19 14/19 0/19 19/19 19/19 19/19 19/19 19/19 19/19 15/19 0/19 0/19 8/19 16/19 18/19 18/19 19/19 19/19 19/19 18/19 18/19 18/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 0/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 11/19 18/19 19/19 19/19 19/19 19/19 19/19 19/19 0/19 0/19 17/19 19/19 18/19 0/19 13/19 17/19 19/19 19/19 19/19 19/19 19/19 19/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 11/19 18/19 19/19 19/19 19/19 0/19 16/19
§basic functionality No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§constructor arguments No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§constructor requires new No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§constructor accepts null No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§constructor invokes set No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§iterator closing No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Map.prototype.set returns this No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§-0 key converts to +0 No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§Map.prototype.size MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Map.prototype.delete MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Map.prototype.clear MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Map.prototype.forEach MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Map.prototype.keys MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Map.prototype.values MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Map.prototype.entries MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Map.prototype[Symbol.iterator] MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§Map.prototype isn't an instance No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Map iterator prototype chain No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§Map[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Set MDN (Mozilla Development Network) logo  0/19 14/19 19/19 14/19 0/19 19/19 19/19 19/19 19/19 19/19 19/19 15/19 0/19 0/19 8/19 16/19 18/19 18/19 19/19 19/19 19/19 18/19 18/19 18/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 0/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 11/19 18/19 19/19 19/19 19/19 19/19 19/19 19/19 0/19 0/19 18/19 19/19 18/19 0/19 13/19 17/19 19/19 19/19 19/19 19/19 19/19 19/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 11/19 18/19 19/19 19/19 19/19 0/19 16/19
§basic functionality No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§constructor arguments No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§constructor requires new No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§constructor accepts null No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§constructor invokes add No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§iterator closing No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Set.prototype.add returns this No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§-0 key converts to +0 No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§Set.prototype.size MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Set.prototype.delete MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Set.prototype.clear MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Set.prototype.forEach MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Set.prototype.keys MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Set.prototype.values MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Set.prototype.entries MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Set.prototype[Symbol.iterator] MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§Set.prototype isn't an instance No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§Set iterator prototype chain No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§Set[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§WeakMap MDN (Mozilla Development Network) logo  0/12 6/12 12/12 9/12 0/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 0/12 6/12 11/12 11/12 11/12 12/12 12/12 12/12 10/12 11/12 11/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 7/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 9/12 11/12 11/12 0/12 7/12 11/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 7/12 12/12 12/12 12/12 12/12 0/12 10/12
§basic functionality No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§constructor arguments No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§constructor requires new No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§constructor accepts null No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§constructor invokes set No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§frozen objects as keys No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§iterator closing No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§WeakMap.prototype.set returns this MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§WeakMap.prototype.delete MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§no WeakMap.prototype.clear method MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§.has, .get and .delete methods accept primitives No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No ? ? ? No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§WeakMap.prototype isn't an instance No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§WeakSet MDN (Mozilla Development Network) logo  0/11 5/11 11/11 8/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 0/11 0/11 10/11 10/11 10/11 11/11 11/11 11/11 9/11 10/11 10/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 9/11 10/11 10/11 0/11 6/11 10/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 11/11 11/11 11/11 11/11 0/11 9/11
§basic functionality No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No Yes Yes Yes Yes No Yes
§constructor arguments No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§constructor requires new No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§constructor accepts null No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No Yes Yes Yes Yes No Yes
§constructor invokes add No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§iterator closing No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§WeakSet.prototype.add returns this No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§WeakSet.prototype.delete No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No Yes Yes Yes Yes No Yes
§no WeakSet.prototype.clear method No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§.has and .delete methods accept primitives No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No ? ? ? No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§WeakSet.prototype isn't an instance No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No Yes Yes Yes Yes No Yes
§Proxy MDN (Mozilla Development Network) logo [20] 0/34 0/34 0/34 0/34 0/34 0/34 0/34 0/34 0/34 0/34 0/34 0/34 0/34 0/34 0/34 34/34 34/34 34/34 34/34 34/34 34/34 30/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 0/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 0/34 0/34 34/34 34/34 34/34 34/34 34/34 34/34 0/34 0/34 27/34 34/34 0/34 0/34 0/34 0/34 34/34 34/34 34/34 34/34 34/34 34/34 1/34 1/34 1/34 1/34 11/34 11/34 15/34 0/34 0/34 0/34 0/34 34/34 34/34 34/34 0/34 0/34
§constructor requires new No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§no "prototype" property No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§"get" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§"get" handler, instances of proxies No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"get" handler invariants No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§"set" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§"set" handler, instances of proxies No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"set" handler invariants No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§"has" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§"has" handler, instances of proxies No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"has" handler invariants No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§"deleteProperty" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§"deleteProperty" handler invariant No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§"getOwnPropertyDescriptor" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"getOwnPropertyDescriptor" handler invariants No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"defineProperty" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"defineProperty" handler invariants No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"getPrototypeOf" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"getPrototypeOf" handler invariant No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"setPrototypeOf" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"setPrototypeOf" handler invariant No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"isExtensible" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"isExtensible" handler invariant No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"preventExtensions" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"preventExtensions" handler invariant No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"ownKeys" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No
§"ownKeys" handler invariant No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§"apply" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No Yes No No No No Yes Yes Yes No No
§"apply" handler invariant No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No Yes No No No No Yes Yes Yes No No
§"construct" handler MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No Yes No No No No Yes Yes Yes No No
§"construct" handler invariants No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No Yes No No No No Yes Yes Yes No No
§Proxy.revocable MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.isArray support No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§JSON.stringify support No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Reflect MDN (Mozilla Development Network) logo [21] 0/20 0/20 15/20 14/20 0/20 15/20 15/20 15/20 15/20 15/20 15/20 14/20 0/20 0/20 0/20 13/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 0/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 0/20 0/20 20/20 20/20 20/20 20/20 20/20 20/20 0/20 0/20 14/20 16/20 0/20 0/20 0/20 0/20 20/20 20/20 20/20 20/20 20/20 20/20 6/20 6/20 6/20 6/20 14/20 14/20 14/20 0/20 0/20 0/20 0/20 20/20 20/20 20/20 0/20 0/20
§Reflect.get MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.set MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.has MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.deleteProperty MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.getOwnPropertyDescriptor MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.defineProperty MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.getPrototypeOf MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.setPrototypeOf MDN (Mozilla Development Network) logo  No No No[16] No[16] No No[16] No[16] No[16] No[16] No[16] No[16] No[16] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.isExtensible MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.preventExtensions MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.ownKeys, string keys MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.ownKeys, symbol keys MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.apply MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.construct MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.construct sets new.target meta-property No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Reflect.construct creates instances from third argument No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Reflect.construct, Array subclassing No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No ? ? No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Reflect.construct, RegExp subclassing No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No ? ? No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Reflect.construct, Function subclassing No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No ? ? No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Reflect.construct, Promise subclassing No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No ? ? No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Promise MDN (Mozilla Development Network) logo  0/8 4/8 8/8 7/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 7/8 0/8 0/8 0/8 7/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 4/8 6/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 0/8 4/8 8/8 0/8 0/8 4/8 7/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 5/8 4/8 6/8 8/8 8/8 8/8 0/8 0/8
§basic functionality MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes No No
§constructor requires new No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No Yes No No Yes Yes Yes No No
§Promise.prototype isn't an instance No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes No No
§Promise.all MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes No No
§Promise.all, generic iterables No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Promise.race MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes No No
§Promise.race, generic iterables No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Promise[Symbol.species] No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol MDN (Mozilla Development Network) logo  0/12 4/12 9/12 2/12 0/12 8/12 8/12 8/12 8/12 8/12 8/12 2/12 0/12 0/12 0/12 10/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 11/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 4/12 12/12 12/12 0/12 9/12 10/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 0/12 0/12 11/12 12/12 12/12 0/12 0/12 0/12 11/12 12/12 12/12 12/12 0/12 11/12
§basic functionality No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes No Yes
§typeof support No Yes Yes[11] No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes No Yes
§symbol keys are hidden to pre-ES6 code No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes No Yes
§Object.defineProperty support No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes No Yes
§symbols inherit from Symbol.prototype No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes No Yes
§cannot coerce to string or number No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No Yes
§can convert with String() No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§new Symbol() throws No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No Yes
§Object(symbol) No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No Yes Yes Flag Flag No Yes Yes Yes Yes No Yes
§JSON.stringify ignores symbol primitives No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No Yes
§JSON.stringify ignores symbol objects No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No Yes
§global symbol registry No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No Yes
§well-known symbols[22] 0/26 1/26 15/26 1/26 0/26 15/26 15/26 15/26 15/26 15/26 15/26 0/26 0/26 0/26 0/26 3/26 9/26 10/26 17/26 17/26 17/26 8/26 26/26 26/26 26/26 26/26 26/26 26/26 26/26 26/26 26/26 26/26 0/26 25/26 26/26 26/26 26/26 26/26 26/26 26/26 26/26 26/26 26/26 26/26 0/26 3/26 26/26 26/26 26/26 26/26 26/26 26/26 0/26 0/26 23/26 25/26 22/26 0/26 2/26 3/26 26/26 26/26 25/26 26/26 26/26 26/26 0/26 0/26 0/26 0/26 1/26 1/26 1/26 0/26 0/26 0/26 3/26 26/26 26/26 26/26 0/26 1/26
§Symbol.hasInstance MDN (Mozilla Development Network) logo  No No Flag No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.isConcatSpreadable MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.iterator, existence MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No Yes
§Symbol.iterator, arguments object No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Symbol.species, existence MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.species, Array.prototype.concat No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.species, Array.prototype.filter No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.species, Array.prototype.map No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.species, Array.prototype.slice No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.species, Array.prototype.splice No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.species, RegExp.prototype[Symbol.split] No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.species, Promise.prototype.then No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No ? ? No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.replace MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.search MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.split MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.match MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.match, RegExp constructor No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.match, String.prototype.startsWith No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.match, String.prototype.endsWith No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.match, String.prototype.includes No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.toPrimitive MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.toStringTag MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.toStringTag affects existing built-ins No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Flag Yes Yes No Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.toStringTag, new built-ins No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.toStringTag, misc. built-ins No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Symbol.unscopables MDN (Mozilla Development Network) logo  No No No No No No[7] No[7] No[7] No[7] No[7] No[7] No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No[23] Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
Built-in extensions
§Object static methods 0/4 3/4 3/4 2/4 0/4 3/4 3/4 3/4 3/4 3/4 3/4 2/4 1/4 0/4 1/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 4/4 4/4 4/4 0/4 3/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 1/4 1/4 0/4 4/4 4/4 4/4 4/4 1/4 2/4
§Object.assign MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§Object.is MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes No No
§Object.getOwnPropertySymbols MDN (Mozilla Development Network) logo  No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No Yes
§Object.setPrototypeOf MDN (Mozilla Development Network) logo  No No No[16] No[16] No No[16] No[16] No[16] No[16] No[16] No[16] No[16] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes
§function "name" property MDN (Mozilla Development Network) logo  0/17 0/17 8/17 0/17 0/17 3/17 3/17 3/17 3/17 3/17 3/17 0/17 3/17 0/17 0/17 8/17 14/17 16/17 16/17 16/17 16/17 10/17 12/17 12/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 2/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 3/17 6/17 17/17 17/17 17/17 17/17 17/17 17/17 3/17 3/17 5/17 17/17 14/17 2/17 2/17 6/17 17/17 17/17 17/17 17/17 17/17 17/17 0/17 0/17 0/17 0/17 7/17 7/17 7/17 2/17 2/17 3/17 6/17 17/17 17/17 17/17 2/17 3/17
§function statements No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§function expressions No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§new Function No No No No No No No No No No No No Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No[0] Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes No No
§bound functions No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§variables (function) No No Yes[11] No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] Flag[10] No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§object methods (function) No No Yes[11] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§accessor properties No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§shorthand methods No No Yes[11] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No Yes
§shorthand methods (no lexical binding) No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§symbol-keyed methods No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§class statements No No No[24] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§class expressions No No No[24] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§variables (class) No No No[24] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§object methods (class) No No No No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§class prototype methods No No Yes[11] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§class static methods No No Yes[11] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§isn't writable, is configurable No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§String static methods 0/2 2/2 2/2 1/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 0/2 1/2 1/2 1/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 0/2 0/2
§String.raw MDN (Mozilla Development Network) logo  No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§String.fromCodePoint MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§String.prototype methods 0/10 8/10 9/10 7/10 0/10 9/10 9/10 9/10 9/10 9/10 9/10 7/10 0/10 0/10 0/10 9/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 9/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 0/10 9/10 10/10 10/10 0/10 1/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 0/10 0/10 0/10 2/10 7/10 7/10 0/10 0/10 0/10 9/10 10/10 10/10 10/10 0/10 2/10
§String.prototype.codePointAt MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§String.prototype.normalize MDN (Mozilla Development Network) logo  No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§String.prototype.repeat MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes No No
§String.prototype.startsWith MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes Flag Flag No Yes Yes Yes Yes No No
§String.prototype.startsWith throws on RegExp No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes No No No Yes Yes Yes Yes No No
§String.prototype.endsWith MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes Flag Flag No Yes Yes Yes Yes No No
§String.prototype.endsWith throws on RegExp No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes No No No Yes Yes Yes Yes No No
§String.prototype.includes MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag[0] Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes No[0] No[0] No Yes Yes Yes Yes No No
§String.prototype[Symbol.iterator] MDN (Mozilla Development Network) logo  No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§String iterator prototype chain No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§RegExp.prototype properties MDN (Mozilla Development Network) logo  0/6 0/6 6/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 1/6 0/6 0/6 0/6 0/6 1/6 1/6 1/6 1/6 1/6 1/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 1/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 6/6 6/6 5/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 1/6 1/6 1/6 0/6 0/6 0/6 1/6 6/6 6/6 6/6 0/6 0/6
§RegExp.prototype.flags MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§RegExp.prototype[Symbol.match] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp.prototype[Symbol.replace] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp.prototype[Symbol.split] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp.prototype[Symbol.search] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array static methods 0/11 10/11 11/11 5/11 0/11 9/11 9/11 9/11 9/11 9/11 9/11 7/11 0/11 0/11 0/11 7/11 10/11 10/11 11/11 11/11 11/11 10/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 8/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 6/11 11/11 8/11 0/11 0/11 9/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 8/11 11/11 11/11 11/11 0/11 0/11
§Array.from, array-like objects MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Array.from, generator instances No Yes Yes Yes No No[7] No[7] No[7] No[7] No[7] No[7] Yes No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.from, generic iterables No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Array.from, instances of generic iterables No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Array.from map function, array-like objects No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Array.from map function, generator instances No Yes Yes No No No[7] No[7] No[7] No[7] No[7] No[7] Yes No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.from map function, generic iterables No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Array.from map function, instances of iterables No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Array.from, iterator closing No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Array.of MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Array[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype methods 0/10 7/10 10/10 8/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 7/10 0/10 0/10 0/10 9/10 10/10 10/10 10/10 10/10 10/10 8/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 0/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 5/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 0/10 9/10 10/10 10/10 0/10 5/10 8/10 10/10 9/10 9/10 9/10 9/10 9/10 0/10 0/10 0/10 0/10 0/10 0/10 0/10 0/10 0/10 5/10 10/10 10/10 10/10 10/10 0/10 5/10
§Array.prototype.copyWithin MDN (Mozilla Development Network) logo  No No Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Array.prototype.find MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag Yes Yes Yes Yes Yes No No
§Array.prototype.findIndex MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag Yes Yes Yes Yes Yes No No
§Array.prototype.fill MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§Array.prototype.keys MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag Yes Yes Yes Yes Yes No Yes
§Array.prototype.values MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes No[25] No[26] No[26] No[26] No[26] No[26] No[26] No[26] No[26] No[26] No[26] No No[27] No[27] No[27] No[27] No[27] No[27] No[27] No[27] No[27] No[27] No[27] No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes No Yes No[27] No[27] No[27] No[27] No[27] No No No No No No No Flag Flag No Yes Yes Yes Yes No Yes
§Array.prototype.entries MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag Yes Yes Yes Yes Yes No Yes
§Array.prototype[Symbol.iterator] MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§Array iterator prototype chain No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§Array.prototype[Symbol.unscopables] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Number properties 0/9 7/9 9/9 7/9 0/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 6/9 0/9 0/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 0/9 7/9 7/9 7/9 0/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 2/9 2/9 0/9 9/9 9/9 9/9 9/9 0/9 0/9
§Number.isFinite MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes No Yes Yes Yes Yes No No
§Number.isInteger MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Number.isSafeInteger MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Number.isNaN MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes No Yes Yes Yes Yes No No
§Number.parseFloat MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Number.parseInt MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Number.EPSILON MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Number.MIN_SAFE_INTEGER MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Number.MAX_SAFE_INTEGER MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Math methods 0/17 17/17 17/17 16/17 0/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 14/17 0/17 0/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 0/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 15/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 0/17 0/17 17/17 17/17 17/17 0/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 0/17 0/17 0/17 0/17 5/17 5/17 8/17 1/17 1/17 15/17 17/17 17/17 17/17 17/17 0/17 0/17
§Math.clz32 MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No Yes No No No Yes Yes Yes Yes No No
§Math.imul MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No
§Math.sign MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No Yes No Flag No Yes Yes Yes Yes No No
§Math.log10 MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes No No
§Math.log2 MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes No No
§Math.log1p MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§Math.expm1 MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§Math.cosh MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§Math.sinh MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§Math.tanh MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§Math.acosh MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§Math.asinh MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§Math.atanh MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§Math.trunc MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes No No
§Math.fround MDN (Mozilla Development Network) logo  No Yes Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No No
§Math.cbrt MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes No No
§Math.hypot MDN (Mozilla Development Network) logo  No Yes Yes[11] Yes No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes No No
§Date.prototype[Symbol.toPrimitive] MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
Subclassing
§Array is subclassable 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 11/11 11/11 11/11 11/11 11/11 6/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 3/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 11/11 11/11 11/11 0/11 0/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 3/11 11/11 11/11 11/11 0/11 0/11
§length property (accessing) No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§length property (setting) No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§correct prototype chain No No No[16] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.isArray support No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Array.prototype.concat No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.filter No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.map No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.slice No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.splice No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.from No No[16] No[16] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.of No No[16] No[16] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp is subclassable 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 3/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 4/4 4/4 4/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 3/4 4/4 4/4 4/4 0/4 0/4
§basic functionality No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§correct prototype chain No No No[16] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp.prototype.exec No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§RegExp.prototype.test No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Function is subclassable 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 6/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 0/6 0/6
§can be called No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§correct prototype chain No No No[16] No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§can be used with "new" No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Function.prototype.call No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Function.prototype.apply No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Function.prototype.bind No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Promise is subclassable 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 2/4 4/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 0/4 0/4
§basic functionality No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§correct prototype chain No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Promise.all No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Promise.race No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§miscellaneous subclassables 0/6 0/6 0/6 2/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 6/6 6/6 6/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 0/6 0/6
§Boolean is subclassable No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Number is subclassable No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§String is subclassable No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Error is subclassable No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Map is subclassable No No No Yes No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Set is subclassable No No No Yes No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
Misc
§prototype of bound functions 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 4/5 5/5 3/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 1/5 1/5 1/5 1/5 1/5 1/5 1/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 0/5 0/5
§basic functions No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No
§generator functions No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§arrow functions No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§classes No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§subclasses No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Proxy, internal 'get' calls MDN (Mozilla Development Network) logo  0/36 0/36 0/36 0/36 0/36 0/36 0/36 0/36 0/36 0/36 0/36 0/36 0/36 0/36 0/36 14/36 19/36 20/36 24/36 24/36 24/36 22/36 35/36 35/36 35/36 35/36 36/36 36/36 36/36 36/36 36/36 36/36 0/36 36/36 36/36 36/36 36/36 36/36 36/36 36/36 36/36 36/36 36/36 36/36 0/36 0/36 35/36 35/36 35/36 35/36 36/36 36/36 0/36 0/36 19/36 34/36 0/36 0/36 0/36 0/36 35/36 35/36 35/36 36/36 36/36 36/36 0/36 0/36 0/36 0/36 7/36 7/36 8/36 0/36 0/36 0/36 0/36 35/36 35/36 35/36 0/36 0/36
§ToPrimitive No No No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§CreateListFromArrayLike No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§instanceof operator No No No No No No No No No No No No No No No No No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§HasBinding No No No No No No No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No[23] Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§CreateDynamicFunction No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No Yes No No No No Yes Yes Yes No No
§ClassDefinitionEvaluation No No No No No No No No No No No No No No No Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§IteratorComplete, IteratorValue No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§ToPropertyDescriptor No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Object.assign No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Object.defineProperties No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Function.prototype.bind No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Error.prototype.toString No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§String.raw No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp constructor No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp.prototype.flags No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp.prototype.test No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp.prototype.toString No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No ? No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§RegExp.prototype[Symbol.match] No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp.prototype[Symbol.replace] No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§RegExp.prototype[Symbol.search] No No No No No No No No No No No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes No No No No No No No No No No No Yes Yes Yes No No No No No No No No No No No No No No No No
§RegExp.prototype[Symbol.split] No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.from No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.concat No No No No No No No No No No No No No No No No No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype iteration methods No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.pop No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.prototype.reverse No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.shift No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.prototype.splice No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.toString No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§JSON.stringify No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Promise resolve functions No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§String.prototype.match No No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§String.prototype.replace No No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§String.prototype.search No No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§String.prototype.split No No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Date.prototype.toJSON No No No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Proxy, internal 'set' calls MDN (Mozilla Development Network) logo  0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 3/11 11/11 0/11 0/11 0/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 0/11 0/11 7/11 7/11 7/11 0/11 0/11 0/11 0/11 11/11 11/11 11/11 0/11 0/11
§Object.assign No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.from No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.of No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.copyWithin No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.fill No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.pop No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.prototype.push No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.prototype.reverse No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.prototype.shift No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.prototype.splice No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.prototype.unshift No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Proxy, internal 'defineProperty' calls MDN (Mozilla Development Network) logo  0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 2/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 0/2 0/2
§[[Set]] No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§SetIntegrityLevel No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Proxy, internal 'deleteProperty' calls MDN (Mozilla Development Network) logo  0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 1/6 6/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 5/6 5/6 5/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 0/6 0/6
§Array.prototype.copyWithin No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Array.prototype.pop No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.prototype.reverse No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.prototype.shift No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.prototype.splice No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Array.prototype.unshift No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Proxy, internal 'getOwnPropertyDescriptor' calls MDN (Mozilla Development Network) logo  0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 2/4 4/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 0/4 0/4
§[[Set]] No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Object.assign No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Object.prototype.hasOwnProperty No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Function.prototype.bind No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§Proxy, internal 'ownKeys' calls MDN (Mozilla Development Network) logo  0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 3/3 3/3 0/3 0/3 0/3 0/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 0/3 0/3 1/3 1/3 1/3 0/3 0/3 0/3 0/3 3/3 3/3 3/3 0/3 0/3
§SetIntegrityLevel No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§TestIntegrityLevel No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§SerializeJSONObject No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Object static methods accept primitives 0/10 0/10 10/10 0/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 0/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 0/10 9/10 10/10 10/10 0/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 0/10 0/10 0/10 10/10 10/10 10/10 0/10 0/10 0/10 10/10 10/10 10/10 10/10 0/10 0/10
§Object.getPrototypeOf MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§Object.getOwnPropertyDescriptor MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§Object.getOwnPropertyNames MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§Object.seal MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§Object.freeze MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§Object.preventExtensions MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§Object.isSealed MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§Object.isFrozen MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§Object.isExtensible MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§Object.keys MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§own property order 0/7 0/7 1/7 0/7 0/7 1/7 1/7 1/7 1/7 1/7 1/7 1/7 0/7 4/7 4/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 4/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 4/7 5/7 7/7 7/7 7/7 7/7 7/7 7/7 0/7 2/7 3/7 7/7 5/7 3/7 3/7 3/7 7/7 7/7 7/7 7/7 7/7 7/7 0/7 0/7 0/7 0/7 6/7 6/7 7/7 3/7 3/7 4/7 5/7 7/7 7/7 7/7 2/7 2/7
§Object.keys No No No No No No No No No No No No ? Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes ? Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Object.getOwnPropertyNames No No No No No No No No No No No No No Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes No No
§Object.assign No No No No No No No No No No No No No No No Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No No
§JSON.stringify No No No No No No No No No No No No No Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No
§JSON.parse No No No No No No No No No No No No No Yes[28] Yes[28] Yes[28] Yes[28] Yes[28] Yes[28] Yes[28] Yes[28] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Reflect.ownKeys, string key order No No No[29] No[29] No No[29] No[29] No[29] No[29] No[29] No[29] No[29] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Reflect.ownKeys, symbol key order No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No No No Yes No No No No Yes Yes Yes No No
§Updated identifier syntax 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 0/3 0/3 1/3 1/3 1/3 1/3 3/3 3/3 3/3 3/3 1/3 1/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 1/3 1/3 1/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 0/3 0/3 0/3 1/3 1/3 0/3 0/3 0/3 1/3 1/3 1/3 3/3 3/3 3/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 1/3 1/3 1/3 1/3 0/3 1/3
§var ⸯ; ? ? ? ? ? ? ? ? ? ? ? ? No No No ? ? Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No ? ? Yes Yes Yes Yes Yes Yes Yes Yes Yes ? ? ? ? ? ? ? No ? ? No ? ? ? ? ? ? ? ? Yes Yes Yes No No No No ? ? No ? ? ? ? ? ? ? No No
§var 𐋀; ? ? ? ? ? ? ? ? ? ? ? ? No No No ? ? Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No ? ? Yes Yes Yes Yes Yes Yes Yes Yes Yes ? ? ? ? ? ? ? No ? ? No ? ? ? ? ? ? ? ? Yes Yes Yes No No No No ? ? No ? ? ? ? ? ? ? No No
§no escaped reserved words as identifiers Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes ? No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes ? Yes Yes Yes Yes Yes Yes Yes ? ? No Yes Yes ? ? ? Yes Yes Yes Yes Yes Yes No No No No No No No ? ? ? Yes Yes Yes Yes No Yes
§miscellaneous 0/9 0/9 5/9 2/9 0/9 5/9 5/9 5/9 5/9 5/9 5/9 2/9 1/9 2/9 2/9 6/9 6/9 6/9 7/9 7/9 7/9 7/9 7/9 8/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 2/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 2/9 4/9 9/9 9/9 9/9 9/9 9/9 9/9 2/9 2/9 5/9 7/9 8/9 2/9 2/9 6/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 0/9 0/9 0/9 7/9 7/9 7/9 2/9 2/9 2/9 4/9 9/9 9/9 9/9 2/9 4/9
§duplicate property names in strict mode No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes No Yes
§no semicolon needed after do-while No No Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§no assignments allowed in for-in head in strict mode No No Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§accessors aren't constructors No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§Invalid Date No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§RegExp constructor can alter flags No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§RegExp.prototype.toString generic and uses "flags" property No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No ? ? Yes No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
§built-in prototypes are not instances No No No No No No No No No No No No No No No No No Flag[10] Flag[10] Flag[10] Flag[10] No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No No Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§function 'length' is configurable No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes No No
Annex b
§non-strict function semantics[30] 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 2/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 2/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 2/3 0/3 2/3 3/3 2/3 2/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 0/3 0/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 3/3 3/3 3/3 0/3 1/3
§hoisted block-level function declaration No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No Yes No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes No No
§labeled function statements No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes
§function statements in if-statement clauses No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No
§__proto__ in object literals MDN (Mozilla Development Network) logo [31] 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 1/5 0/5 1/5 3/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 1/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 2/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 1/5 1/5 0/5 5/5 5/5 1/5 1/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 1/5 1/5 2/5 5/5 5/5 5/5 5/5 1/5 3/5
§basic support No No No No No No No No No No No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes
§multiple __proto__ is an error No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No Yes
§not a computed property No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes No Yes
§not a shorthand property No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§not a shorthand method No No No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes No No
§Object.prototype.__proto__ MDN (Mozilla Development Network) logo  0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 3/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 4/6 6/6 2/6 6/6 6/6 2/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 1/6 1/6 1/6 1/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6
§get prototype No No No No No No No No No No No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§set prototype No No No No No No No No No No No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§absent from Object.create(null) No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§present in hasOwnProperty() No No No No No No No No No No No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§correct property descriptor No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§present in Object.getOwnPropertyNames() No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§String.prototype HTML methods 0/3 0/3 3/3 0/3 0/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 1/3 1/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3
§existence MDN (Mozilla Development Network) logo  No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes No No
§tags' names are lowercase No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes No No
§quotes in arguments are escaped No No Yes[11] No No Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes[14] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes No No
§RegExp.prototype.compile MDN (Mozilla Development Network) logo  0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 1/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 1/2 1/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 1/2 1/2 2/2 2/2 2/2 2/2 2/2 2/2 1/2 1/2 0/2 1/2 0/2 1/2 1/2 1/2 1/2 1/2 1/2 2/2 2/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 1/2 1/2 1/2 1/2 2/2 2/2 2/2 2/2 2/2
§basic functionality No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes
§returns this No No No No No No No No No No No No ? Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes ? No No ? No No No No No No No Yes Yes Yes No No No No No No No No No No No Yes Yes Yes Yes Yes
§RegExp syntax extensions 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 6/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 4/8 5/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 0/8 0/8 0/8 3/8 3/8 3/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 7/8 7/8
§hyphens in character sets No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§invalid character escapes No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§invalid control-character escapes No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes
§invalid Unicode escapes No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes
§invalid hexadecimal escapes No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes
§incomplete patterns and quantifiers No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§octal escape sequences No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes No No
§invalid backreferences become octal escapes No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes
§HTML-style comments No No No No No No No No No No No No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No No
__createIterableObject(), used in the numerous "generic iterables" tests, is defined as:

[1] Flagged features have to be enabled via "Experimental Javascript features" flag unless otherwise stated

[2] Flagged features require an optional transformer setting.

[3] Results are only applicable for the KHTML rendering engine.

[4] Flagged features have to be enabled via --harmony flag

[5] Flagged features have to be enabled via --harmony or --es_staging flag

[6] Requires the properTailCalls compile option.

[7] TypeScript's compiler will accept code using this feature if the --target ES6 flag is set, but passes it through unmodified and does not supply a runtime polyfill.

[8] The feature have to be enabled via --js-flags="--harmony" flag

[9] The feature is considered unstable, but can be enabled via --js-flags="--harmony-tailcalls" flag

[10] Flagged features have to be enabled via "Enable experimental Javascript features" setting under about:flags

[11] This feature is supported when using Babel with core-js.

[12] This compiler requires generic iterables have either a Symbol.iterator or non-standard "@@iterator" method.

[13] Firefox incorrectly produces an error in strict mode if the method is named "arguments", "eval", or "delete".

[14] This feature is supported when using TypeScript with core-js.

[15] Note that prior to ES6, it was recommended that ES5 implementations forbid block-level declarations in strict mode.

[16] Requires native support for Object.prototype.__proto__

[17] This compiler transforms extends into code that uses native Object.prototype.__proto__ or copies properties from the superclass, instead of using the prototype chain.

[18] TypeScript transforms extends into code that copies static properties from the superclass (but uses the prototype chain for instance properties).

[19] This feature requires native generators or regenerator-runtime, it's a part of babel-polyfill or babel-runtime.

[20] The 2015 version of the specification also specifies an "enumerate" handler, which was removed in the 2016 version.

[21] The 2015 version of the specification also specifies Reflect.enumerate, which was removed in the 2016 version.

[22] Functionality for Symbol.iterator is tested by the "generic iterators" subtests for the spread (...) operator, for..of loops, destructuring, yield *, and Array.from.

[23] with is not supported in ejs

[24] Requires function "name" properties to be natively configurable

[25] Available from Firefox 36 up to 47 as Array.prototype[Symbol.iterator]

[26] The feature is enabled only in Firefox Nightly due to a compatibility issue.

[27] The feature was disabled due to a compatibility issue.

[28] Unlike other engines, Chakra sorts properties removed by delete, then recreated by assignment, to their original creation positions, not their latest positions.

[29] This uses native for-in enumeration order, rather than the correct order.

[30] The 2015 version of the specification contains multiple bugs for hoisted block-level function declaration semantics, which these tests disregard.

[31] Note that this is distinct from the existence or functionality of Object.prototype.__proto__.